Centrifugal separator



H. G. cHATAlN l 2,292,950

CENTRIF'UGAL SEPARATOR Filed July 2l, 1939 5 Sheets-Sheet 2 I Aug; 11,1942. H. G. CHATAIN 2,292,990A

CENTRIFGAL SEPARATOR Filed July 2l, 1939 5 Sheets-Sheet 5 @L g @2% EYAug. ll, 1942. H. G. cHATAlN CENTRIFUGAL sE'PARAToR Filed'July 21, 19595 sheets-sheet 4 ATT RNEY.

A118- 11, 1942 H. G. cHA'rA'lN 2,292,990

' CENTRIFUGAL sEPARAToR Filed July 21, 1939 v 5 Sheets-Sheet 5 i l lMATT RNr-:Y

Patente-d Aug. 11, 1942 AUNITED STATES PATENT OFFICE CENTRIFUGALSEPARATOR Henri G. Chatain, Erie, Pa.

Application July 21, 1939; Serial No. 285,667

Claims.

The invention relates to method and means for filtering or extractingliquids from solids. More particularly it relates to improvements incentrifugal separators of the'continuous type as distinguished fromthose designed for batch operation.

Centrifugal separators of the continuous type generally provide forcontinuousfeeding ofthe stock at a controlled rate and for continuousdischarge ofthe separated liquid fraction or fractions. Discharge of thesolid fractions may be either continuous or intermittent. Attempts toprovide for continuous discharge ofY the solid fraction have beenlattended with serious difficulties, particularly as applied to thetreatment of brous materials or other materials yielding a solidfraction which does not flow readily. Movement of the solid fractiontoward the point of discharge has been accomplished, or proposed to beaccomplished, in many different ways. For example, it has been-proposedto use helical-con- Veyors; Scrapers which exert a raking action on thematerial; ldisc harrows; or pistons which push the materiall toward thepoint of discharge. While suchl devices may have merit as applied to theseparation of liquids from certain classes ofrnaterial, they are notwell adapted to the treatment of materials of a `fibrouscharacter such`aspaper pulp, fibrous cellulose, acetate, and nitrate, certain sludgesfrom sewage and other materials in the sugar, rubber and fibrous boardindustries. The solid fraction of such materialsV tends to clog ahelical conveyor; and rakes or Scrapers which intermittently lift awayfrom the surface of a centrifugal filter basket do not readily get downthrough the material on succeeding bites as the density of the solidsincreases during centrifuging. Again, p-istons which push thematerialtoward the point of discharge tend to distort the cake of solids,leading to lack of uniformity in extraction and adversely affecting thelength of time required to achieve a given percentage of reduction inmoisture content. With such a method the cake does not maintain auniform thickness, but will frequently hump up, thereby increasing thedifficulty of extracting the liquor. It is an object of my invention toprovide a method and means for continuous centrifugal separation ofsolid and liquid fractions which overcomes these and other difficulties,and which is particularly advantageous in the centrifuging of fibrousmaterials.

A general object kof the present inventionis to provide means forcontinuously extracting liquids from moist solids more rapidly andefficiently than is possible with methods and apparatus heretoforeknown.

A specific object of my inventionis to provide an improved method andmeans for causing solids to traverse the length of a centrifugal lterbasket Without clogging -or humping.

A further specific object is to provide improved auxiliary pressureextracting means to supplement centrifugal extraction. .Y A furtherobject is to provide an improved form of filter basket. Other objectsand advantages of my invention will appear as the description proceeds.i

As previously noted, one of the principal difficulties experienced inthe centrifuging of fibrous materials, and materials possessingsimilarcaking characteristics, resides in the problem of obtaining auniform discharge of the cake without clogging or humping. Factorsinfluencing removal of the cake in undistorted form are: (l) the densityof the cake; (2) the width of the cake in advance of the pushingelement; (3) the thickness of the cake; (4) the coefficient of frictionbetweenv the cake and the surface of the filter basket; and (5) thecentrifugal force developed by the machine. I have found thatfor a givenmaterial, centrifugal force and cake thickness, improved handling of thecake can be obtained by running ejector blades circumferentially intothe cake at an acute angle to a plane normal to the axis of rotation ofthe filter basket, and intermittently advancing the ejector bladestoward the discharge end of the basket, so that, in effect, the ejectoris screwedinto the cake from the discharge encl and pulls the cake outlike an annular cork. In order to havecontinuous operation this musttake Iplace while the basket and ejector are rotating. Thescrewingin.action is accomplished by having the ejector screw and basketrotate at somewhat different speeds. It is quite essential, inaccordance With my 5preferred method, that the ejector screw enter thecake or advance its position into the cake, substantially without movingthe cake axiallyY of 'the filter basket. In this way very littleresistance is offered to the action of the ejector even with a fibrouscake, or a cake of great density. Axial movement of the cake isperformed intermittently by bodily movement-of the ejector screw and notby a helical conveyor action.

In 'order that the nature and many advantages of my invention Will'befully understood, I shall describe certain preferred embodimentsthereof` with reference to the accompanying drawings, in which Fig. 1`is a vertical longitudinal sectional view of a centrifugal separatorcapable of operation-in accordance with my novel method, and embodyingnovel features of construction to bev described.

Fig'. 2 is a transverse sectional View taken on the line 2 2 of Fig. 1.

Fig. 3 is a detail View of the cam mechanism for intermittentlyadvancing the ejector blades toward the discharge end of the basket;and-Fig. 4 is a transverse sectional View on the line 4-4 of Fig. 3.

tail sectional view on the line III-I of Fig. 9.V

Figs. ll to 13 illustrate another embodiment Vof,

the invention in which the axis of the separator is vertical instead ofhorizontal; Fig. 11 being a central vertical sectional View; Fig. 12 adetail vertical sectional view showing the liquid discharge outlets; andFig. 13 a sectionalview on the line I3-I3 of Fig. ll.

The apparatus comprises, in its general arrangement, a casing I, withinwhich are rotatably mounted a chamber or basket 2 and a helical ejector3. The casing I is provided with an intake conduit, or alimentary pipe,4, arranged to charge the separator with a slurry to be filtered, and isalso provided with an outlet, or series of outlets, 5, for discharge ofthe liquid fractions, and an outlet 6 for discharge of the solids. Thebasket element 2 and ejector element 3 are mounted in association with amain shaft 1 and auxiliary shafts to be described, driven by adifferential mechanism which causes one of said elements to rotate at aslightly higher speed than the other. Means are also provided to produceintermittent movement of one of said elements with respect to the otherin an axial direction, i. e., parallel to the axis of the shaft 1.

As another element of the general combination there may also be provideda discharge ring 8 driven by a planetary transmission from the shaft 1.

The shafts for the rotating elements 2, 3, and 8 are supported onbearings 9 and I8, the supporting rings of which may have sphericalsurfaces for engagement with similar surfaces in the housings II and I2,respectively. These housings are carried on a suitable supporting frame,or base, I3. Keyed to one end of the shaft I is a pulley I4 driven froma suitable source of power. The basket 2 is supported on a pair of quillshafts I5, I6 surrounding the main shaft I and driven therefrom. Thequill shaft I5 is driven from the main shaft 'I through suitablegearing. For this purpose I have shown gears I'I and I8 keyedrespectively to the shafts 'I and I5, gear I'I meshing with a pinion I3keyed to a shaft 20 conveniently carried in the housing 2l whichsurrounds the gearing. Also keyed to the shaft 28 is a pinion 22 whichmeshes with gear I8 previously referred to. In the embodimentillustrated the basket 2 is arranged to rotate at a speed which issomewhat greater than that of the helical ejector. This differentialspeed is produced by the transmission gearing just described. Thepurpose of the speed differential will be explained later.

l Since the quill shaft I3 forms a part of the basket 2, it will beunderstood that the transmission gearing in the housing 2l serves todrive the shaft I6 as well as the shaft I5. The discharge ring 8 isdriven through the shafts 'I and I6. The ring 8 is mounted on spokes 23radiating from a hub 24 having a bearing portion 25 to receive a portionof the quill shaft I6 about which the ring is arranged to rotate. Todrive the ring 8, gears 26 and 21 are keyed, respectively, to the shaftsI6 and 1, and these gears mesh with planetary gears 28 mounted on stubshafts 29 secured to the ange 38 of the hub 24.

There are three sets of these planetary gears 28 as shown in Fig. 2.Inasmuch as the speed differential between the shafts 'I and I6, andtherefore between the gears 28 and 21, is not great, the planetarygearing described causes the ring 8 to rotate much more slowly than thebasket 2. Cooperating with the discharge ring 8 is a scraper 3| (Figs. 1and 2), mounted on the ange 32 secured to the housing I. The angulararrange-- ment of the scraper 3l is such that the material collected onthe discharge ring 8 is scraped o into the discharge outlet 6.

The helical ejector 3 is carried by a quill shaft 33, mounted on themain shaft 'I and keyed toit by a spline 34 in such a manner las to beslidable longitudinally of the shaft 1. Longitudinal movement of theejector is positively controlled, as by cam action, at least during thatportion of its cycle when it is moving to the right as viewed in Fig. l.For this purpose I prefer to employ a cam or cams associated with one orboth of the quill shafts I5 and 33. In the embodiment illustrated I haveprovided a pair of cams 34 and 35 secured, respectively, to the adjacentends of the shafts I5 and 33, and cooperating cam rollers 36, of whichthere may conveniently be two, mounted on stub shafts for rotation in aring 31 which, in turn, is rotatable with respect to the shaft 'I onwhich it has a bearing. One of the cams may have a plane surface, orboth may be undulating or be provided with humps for controllinglongitudinal movement of the quill shaft 33. As illustrated, the cam 35has a plane surface serving as a race for the rollers 36, while cam 34has a surface which, as developed, would appear substantially as shownin Fig. 5, having a pair of humps 33 located apart to correspond withthe spacing of the two rollers 36. The rollers 36 may be mounted on ballor roller bearings as indicated in Fig. 3. If desired, however, therollers 38 can be omitted from the construction shown, and the two camsdesigned for direct engagement with one another. The form of the humps38 is important in achieving certain of the objects of my invention, andwill be described more particularly hereinbelow. If desired, a helicalspring 39 may be provided between the end of the shaft 33 and a collaror flange 4I] on the shaft 'I to insure that the ejector 2 will becorrectly positioned when the apparatus is put into operation; also toassist in the screwing-in action to be described. 'Ielescoping sleeves4I and 42, attached, respectively, to shaft 33 and collar 40, provide ahousing for the spring 39.

The preferred construction of the basket 2 will now -be described withreference principally to Figures 1, 2, 9 and l0. The frame of the basketmay conveniently be in the form of a casting of open cylindrical formhaving spaced circumferential rings 43 joined together by longitudinalmembers 44. The ring members 43 are provided with a series oflongitudinally extending slots 45 (Fig. 10) to receive the wedge-shapedlongitudinal bars 43 which form the inner surface of the basket. Thesebars 46 are so designed and spaced that their inner edges are spacedapart a suitable distance to permit escape of the liquid fraction of thematerial which is to be centrifuged. For paper pulp, fibrous cellulose,acetate and nitrate, certain sludges from sewage and other materials inthe sugar, rubber, and fibrous board industries, I have found thatspacings of v0.004 to 0.010 of an inch give good results. This refers tothe spacing between adjacent bars at the point where they come closesttogether, as shown at 41 in Fig. 10. It will be understood that thespacing of vthe bars depends upon the nature of the materials to beseparated and may be varied in accordance with this factor.` In mypreferred construction the inneredges 48 of the bars which are to formthe inner surface of the basket arearcuate in cross section. I havefound that this form of edge assists the liquid to find its way to theslots `41under the action of centrifugal force. The bars 46 may be heldin place in any convenient manner, and in my preferred construction theends of these bars are slotted as at 49 to receive the peripheral flange59 Aof a clamping ring `5| which is secured to a ange 52 formed on theend ring 43 of the basket frame by means of studs 53 and nuts 54provided at intervals around the periphery of the frame. Thisconstruction is shown best in Fig. 9. At one end o f the basket 2 theclamping ring 5I is secured to the rim 55 of the wheel which has thequill shaft |46 for a hub, and to which it is connected by radial spokes56. The wheel thus formed may be strengthened by the provision ofcircumferential tubular elements 51 which may conveniently pass'throughsuitable apertures in the spokes 56. An end plate 58 is secured to theclamping ring I at the other end of the basket, and this end plate formsthe rim of a wheel of which the quill shaft I5 constitutes la hub, theplate 58 and shaft l5 "being connected by a plurality of,l radial spokes59. The end plate 58 is provided with a flange 60 which may be in theform of a truncated cone, and which cooperates with a flange 6I securedto the end of the casing l to insure that the material charged into theseparator will be directed to the interior of the basket and not nd itsway between the end plate 53 of the basket and the wall of the casing l.

The alimentary pipe 4, through which the material is charged into theapparatus, preferably is of the form shown in Fig. 7, having twobranches 62 which extend in aV generally circumferential direction fromtheir point of connection with the pipe 4 so as to avoid interferencewith the spokes 59. The extremities of the branches 62 may be turnedoutwardly in a radial direction to direct the material toward theperiphery of the rotating basket and ejector.

The construction of the ejector 3 will now be described principally withreference to Figs. 1 and 6. The quill shaft 33 forms the hub of theejector wheel. Radial arms or spokes 63 extend outwardly from the shaft33, six double spokes being shown in the embodiment selected for thepurpose of illustration. The ends of the double spokes 33 are joined bya radial plate 64, the outer edge of which is inclined, as shown in Fig.l. The plates 64 are cut to form a thread which receives the innerhedgesof a helical element 65 formed of a flatv strip the width of whichdecreases in the direction of flow of material through the separator,Ai. e., from left to right as viewed in Fig. 1. The outer edges of thehelical ejector thus formed lie approximately in the plane of a rightcircular cylinder. The inner edges of the helical element of the ejectorlie approximately in the plane of a truncated cone. The reason foradopting this particular construction resides in the fact that the layerof material p-assing through the separator will be thicker at theventering side offthe machine where its liquid content is greater, andprogressively thinner as the cake approaches the discharge end of themachine, becoming more and more compressed and cie-liquefied. The outerdiameter of the ejector 3 is slightly smaller than the inner diameter ofthe basket 2.

In some instances it may be desirable to separate the liquids intoselected fractions, in which event the casing I may be provided with aplurality of partitions 65 arranged circumferentially of the basket 2and opposite intermediate circumferential rings 43 thereof, so as toeffect a separation of the liquid which passes through the openingsbetween successive rings 43. The partitions 66 thus cooperate with theseparate discharge openings 5 previously described in separating thefiltrate fractions. t

It may be found desirable to apply pressure mechanically to the cake asit emerges at the discharge end of the ejector in order to obtain morecomplete extraction of liquid from certain materials which are so formedor of such a character as to require such auxiliary pressing. For thiscondition, it may be desirable to provide pressure rolls designed tosqueeze the cake directly against the inside of the basket. In theembodiment illustrated, I have shown apparatus for this purpose, whichapparatus will now be described principally with reference to Figs. 1 6and 8. This apparatus consists essentially of one or more pressure rolls61 which are pivotally and resiliently connected to the quill shaft 33.For this purpose, shaft 33 has formed thereon or secured thereto, lugs68 (Fig. 8). In the embodiment illustrated, these lugs are formedintegrally with the shaft 331. Pivotally secured to each lug 68 by a pin59 is a bifurcated link 10 designed to pivotally receive the pressureroll 61 between the furcations thereof. The furcations of the link 10are connected near their point of attachment to the lug 68 by a bridgingelement 1I having a surface 12 for engagement with the lug 68 to limitthe movement of the link 1i] about the pivot pin 69 in acounterclockwise direction as viewed in Fig. 8. In this limitingposition it is preferable that there shall be a slight clearance betweenthe roll 61 and the inner surface of the basket 2. The pressure roll isresiliently urged into this limiting position by means of a compressionspring 13 which bears at one end against one of the lugs 68 of the quillshaft 33 and at its other end against a spring seat 14 which ispivotally connected to the link 10 by means of a pin 15. The spring 13is further positioned and guided by a rod 18, one end of which issecured to the spring seat 14 and the other end of which projectsthrough an aperture 11 which extends through the lug 68 and pin 69. Inorder to provide for angling of the rod 16 when the link 10 swings in aclockwise direction about the pivot 69 as indicated by the arrow a inFig. 8, the aperture 11 is flared outwardly at each end as indicated at18, 18. The rod 16 serves to hold the pin 69 against longitudinalmovement, while the pin provides an angularly movable guide for the rod.The furcations of the link 10 may be extended angularly beyond thebearing for the pressure roll 61, as at 19, to provide a support for aknife 80, providing a scraper to keep the surface of the roll free fromaccumulations. It will be understood that as the pressure rolls B1 swingaround the main shaft 1 in the direction indicated by the arrow b (Fig.8) they may also swing about the pivots 69 against the action ofcentrifugal force, and of the spring 1.3, to provide greater or lessclearance between the rolls and the basket as the thickness orcompressibility of the material discharged from the ejector 3 Varies.The rolls are constantly urged outwardly toward the limiting positionshown in Figs. 6 and 8 by centrifugal force augmented by the action ofthe springs 13. I'he principal function of the springs 13 is to hold therolls 61 in their outermost position as the machine is being put intooperation.

If desired, means may be provided for introducing liquids into theinterior of the basket for washing or impregnating the material duringthe process of centrifuging, or for such other purpose as may becontemplated. To this end I have made the shaft 1 of hollow form andprovided it with a series of discharge openings 8l and 82. The ends ofthe shaft 'l are closed by plugs 83 and 84, the latter of which isapertured to receive an inlet pipe 85 for the liquid to be introduced.In the particular embodiment illustrated I have provided for theintroductionof liquids from two sources and have shown a dam 86 dividingthe hollow interior of the shaft into two compartments. Liquid from thepipe 85 enters the one compartment, and a pipe 8l extends through theinterior of the pipe 85 and through an aperture in the dam 86 todischarge liquid into the other compartment. A second dam 88 may beplaced around the inner end of the pipe 85 to confine the liquid in therst chamber. The quill shaft 33, which has been previously described, islongitudinally movable with respect to the shaft 'l which must beprovided with elongated apertures 89 and 90. The apertures 8l, 82, 89and 90 may be arranged at several points around the periphery of theshafts 'l and 33 as shown in Fig. 8. In order to distribute the liquiduniformly over the contents of the basket, there may be as many seriesof outlets as desired, and these may be so arranged that the liquidswill drain principally between selected partitions 43 of the basket andthence be discharged between partitions 66 and through selected outlets5.

As previously mentioned, the drive for the basket and ejector elementsis such that one of them rotates at a somewhat greater speed than theother. The actual speeds depend upon the character of the material whichis to be processed, and upon other factors which have been mentioned.However, in describing the operation of the machine it will beconvenient to assume that for a given material, the Abasket 2 isarranged to rotate at 350 R. P. M. and the ejector 3 at 300 R. P. M.Assuming further that the direction of rotation of the basket andejector is clockwise as viewed in Fig. 6, the helical element 65 of theejector will be in the form of a lefthand screw. Proceeding with these-assumptions, I shall now describe the method of operation of thepreferred embodiment of my apparatus illustrated in Figs. 1 to 10 of thedrawings as follows:

The material to be de-watered is introduced continuously and at asuitable consistency through the alimentary pipe 4 from which it isdischarged into the interior of the machine through the branch pipes 82.It has been explained that the ejector 3 is longitudinally movable alongthe main shaft l and with respect to the basket 2. As the separator isput into operation, the ejector will b-e at the limit of its movement tothe left, as viewed in Fig. 1, under the action of the coil spring 39,the relative position of the cams 34 and 35 being as indicated in Figs.3 and 5, in which the cam rollers 3'6 are in the troughs of the cam 34,permitting the cams to assume that position in which they are closesttogether. The cams 34 and 35 move the ejector 3 to the right against theaction of the spring 39 a distance which is equal to the height of thehumps 38 of the cam 34. In the embodiment illustrated, this distance ison the order of 1 inch and this dimension will be assumed in furtherdiscussion of the operation. This movement of the ejector to the rightoccurs-say-50 times per minute, which will give a discharge of materialequivalent to a cylinder 50 inches long having an outside diameter equalto the inside diameter of the basket 2 and an inside diameter which willdepend upon the thickness of the cake at the discharge end of thehelical element 65.

With the basket 2 rotating in a clockwise direction at 350 R. P. M. andthe ejector 3 rotating in the same direction of 300 R. P. M., theejector is in effect rotating counterclockwise relative to the basket ata speed of 50 R. P. M. This means that the lefthand helical element 65of the ejector screws into the material in the basket, moving from rightto left as viewed in Fig. 1. The material entering the separator isthrown to the periphery of the basket by centrifugal force, where itforms a cake the thickness of which decreases progressively as the cakeapproaches the discharge end. of the machine, becoming more and morecompressed and de-liqueed. This condition is shown in Fig. l. The pitchof the helical element is such that it screws into the cake at a speedwhich brings it to its limit of travel to the left just at the pointwhere the hump 38 of the cam 34 is ready to move the ejector bodily tothe right. The longitudinally inclined portions of the cam 34 which liebeyond the humps 38 preferably are at such an angle as to permit theejector to move to the left at exactly the speed produced by its actionin screwing into the cake. Thus there will be substantially no movementof the cake with respect to the basket during the screwing-in action. Inother words, the helical ejector does not act like a helical conveyor,but rather like a corkscrew which screws into the annular cake and isintermittently pulled toward the discharge opening to produce bodilymovement of the cake in that direction.

If desired, the movement of the ejector to the left may be controlledentirely by the screwingin action, independently of the cam. This mightbe accomplished, for example, by designing the Vcam 34 with a steepslope on both sides of the humps 38, in which case there would actuallybe a clearance between one of the cams and the rollers during thescrewing-in action, and the spring 39 would be so designed as to beinsufciently strong to move the ejector to the left to take up thisclearance (and yet sufficiently strong to take up this clearance at thebeginning of operation when there is no cake in the basket). I prefer,however, to design the cam 34 in the manner first indicated so as toinsure that the ejector will move to the left at a speed which is nogreater than that produced by the screwingin action, in which case thespring 39 can also be made suciently strong to insure that there will beno helical conveying action tending to produce bodily movement of thecake to the right during screwing-in action.

From the foregoing description of the operation of my apparatus, it willbe understood that the helical ejector screws into the material a shortdistance to the left without exerting any helical conveying actionthereon, and is intermittently pushed to the right by the cam action adistance equal to the travel of the ejector during the screwing-inaction. Therefore, considering the 1 inch travel of the ejector aspostulated, it Will be seenthat the action of the ejector is to shiftall of the material in the basket toward the discharge end, ejecting acake of material in the form of a hollow cylinder 1 inch in length.Based on the assumptions previously made as to relative speeds of thebasket and ejector, the action described occurs 50 times per minute andejects 50 inches of material per minute. As each increment isdischarged, it is thrown centrifugally to the discharge ring 8 fromwhich it is removed by the scraper 3| which directs the material intothe discharge opening 6. The liquid fractions are drawn off through thedischarge ports 5, along with such wash water or impregnating liquid asmay be introduced through the pipes 85 and Bl.

It will be understood that the basket and ejec tor could be designed forcounterclockwise rotation insteadV of clockwise rotation, in which casethe helical ejector element 65 would be in the form of a right-handscrew instead of a lefthand screw as shown. Also, it would be possibleto have the ejector rotate at a higher speed than thebasket,remembering` that the direction and pitch of the thread of thehelical ejector must be such as to create the proper screwing-in action,as determined by the direction and magnitude of the speed differential.

Figs. 11-l3` illustrate another embodiment of the invention as appliedto a vertical separator. The casing 9| of this separator is vprovided atits lower end with brackets 92 disposed at convenient points around itsperiphery. The entire unit is supported from pedestals 93 by means ofself-centering supports 94 which, as shown, consist of rods engagingrubber blocks 95 associated with the pedestals 9,3 and with the brackets92, The bottom 96 of the casing 9| is provided with an opening toreceive a bearing support 9'! which, together with the housing 98secured thereto, supports the shafts of the rotating elements of themachine and forms a housing for the gears and cams to be described. Theshafts for said rotating elements are carried by bearings 99, 99 and|00. I iind it convenient to employ `tapered roller bearings at 99, 99Aand a ball bearing at |00. The quill shaft of the basket |02 is carrieddirectly in the bearings 99, 9 9- I'he quill shaft |09 which drives thehelical ejector |04 is rotatably and slidably carried within the quillshaft |0|. Ihe main shaft |05 is keyed to the quill shaft |09 at |00,and drives the quill shaft, |03 through this key, while permitting thequill shaft to slide with respect thereto under the influence of the camaction and screwing-in action to be described.

The construction of the basket |02 and helical ejector |04 issubstantially the same as has been described in connection with theembodiment illustrated in Figs. 1-11, so it is considered unnecessary todescribe this construction in detail. The basket has a perforate surfaceformed by a series of parallel bars clamped together inthe mannerpreviously described. It is mounted on the spokes |0'| attached to a hub|08 secured to the quill shaftv |0|. At its` top it is provided with aplate or shield |09 which corresponds in its general function to theplate 58 of the hori- Zontal separator previously described.

The material which is to be processed is introducedthrough the pipe Y|l0 from which it is directed against a rotating guide plate securedtothe main s haft |05. The periphery of the guide plate preferably isflanged up wardly as at 2 to guide the entering material toward the topo f the helical ejector |04.

The main shaft is driven from any suitable source of power and for thispurpose I have shown a motor ||3 mounted on a bracket ||4 bolted to thebottom 96 of the casing. 'Ihis motor is'connected by suitable belting toa pulley life secured to the main shaft |05. Also secured to the mainshaft is a gear ||9 which meshes with pinions ||l keyed to shafts H8,ilil, to the other ends of which are secured pinions H9, H9. The shaftsH3, ||8 are conveniently carried in the housing member 91, 98. Thepinions H9 mesh with a gear |20 keyed to the quill shaft |0|. 'I he gearratio between the gears and pinions H6, ||1 is slightly different thanthe gear ratio between the pinions ||9 and gear |20 so that the quillshaft |0| is driven from the main shaft |05 at a somewhat differentspeed than shaft |05. The construction which I have shown is designed toproduce a higher speed of rotation of the basket than o-f the ejector,the basket and ejector being driven respectively at the speeds of thequill shaft |0| and main shaft |05. For example, the basket may begeared for rotation at 1000 R. P. M. and the ejector at o `R. P. M.

In this embodiment of the invention the rela` tive bodily movementbetween the basket and ejector is controlled by the` cams |2| and |22,in cooperation with rollers |23 carried by a collar |24 rotatablymounted on the quill shaft |03. The construction and operation of thesecams and rollers may be the saine as has been de-` scribed withreference to the cams34 and 35 and rollers 36 of the horizontalmachine.` The cam |2| is keyed to the gear shaft |0| and the cam |22 iskeyed to the quill shaft`|03 so as to produce relative" longitudinalmovement be'- tween these two quill shafts. Since the ejector |04 ismounted on the quill shaft |03, and the basket on the quill Shaft |0l,Athese cams provide for intermittent longitudinal movementof the ejectorwith respect to the basket. As in the embodiment previously described,the Inovement of the ejector toward the discharge end of the basket (i.Yel, the lower end o f this embodi# ment) is relatively rapid, whereasthe return movement of the ejector is synchronized with the screwing-inaction so as not to produce relative movement of the cake and basketduring the return travel ofthe ejector. In other words, the ejector doesnotact as a spiral conveyor but merely screws Vinto the material in thebasket and pulls it downwardly at intervals by bodily longitudinalmovement. A coil spring |25 is arranged withiir the main shaft |05 so asto bear at one end against the end of the hollow portion of the shaftandat the other end against the key |06 to urge the quill` shaftliitandV thereffore the ejector |04 Vupwardly Y toward its startingposition,`and to take up all clearance between the cams |21, |22 androllers |23. This makes it possible to so design the cams as topositively control the s'upeed of return of the ejector so as tosynchronize it with the screwing-in action and avoid any tendencyY ofthe ejector to act as a helical conveyor. The shafts Il may be three innumber as shown in Fig. 13, each carrying Va pair of gears `||'9. Y,

Mounted for rotation with the helical ejector |04 are two series ofpipes |26 for distributing liquid to the cake in the basket 02. Thesepipes conveniently are attached to the hub |21 of the ejector, which hubin turn is secured to the shaft |03. Apertures |28 and |29, formedrespectively in the shafts |03 and |05, provide communication betweenthe interior of the pipes |26 and the interior of the shaft |05,Apertures |29 are elongated in order to provide for relative movementbetween the shafts |03 and |05 without closing olf communication betweenthe pipe |26 and interior of the shaft |05. Suitable liquids forflushing or impregnating the cake may be introduced in a manner similarto that which has been described in the embodiment of Figs. 1-11inclusive. For this purpose, I have provided a series of dams |30 atspaced intervals along the interior of the shaft in order to divide'itinto separate compartments. Concentric feed pipes |3| and |32communicate respectively with the chambers |33 and |34 thus formed, sothat liquids can be introduced while the machine is in operation. Liquidfrom the upper set of pipes |26, together with a liquid fractionseparated from the material being treated, passes through the basket |02as indicated by the arrows c into the chamber |35 formed between thecasing 9| and a cylindrical wall |36 which is concentric therewith andis spaced therefrom. The wall |36 may be provided with a flange |31 atits upper end to assist in separating the liquid fractions. Liquiddischarged from the lower set of pipes |26, together with a liquidfraction extracted from the material, passes through the basket 02 inthe direction indicated by the arrows d into the chamber |38 formedbetween the cylindrical wall |36 and a second cylindrical wall |39spaced therefrom and concentric therewith. The wall |39 may be providedwith a flange |40 at its upper end to assist in guiding the dischargedliquid fraction into the chamber |38. The liquid fractions aredischarged from the chambers |35 and |38 through ports |4| and |42respectively (Fig. 12). These ports may be provided with flanges, asshown, for connection to suitable pipe lines leading to vats or storagetanks as may be desired. If the basket |02 is rotating at 1000 R. P. M.-and the ejector |04 at 950l R. P. M. this means that there will be aspeed differential of 50 R. P. M. between the cake, which is movingl atthe same speed as the basket, and the pipes |26, which are moving at thesame speed as the ejector. Ihis differential of 50 R. P. M. gives asatisfactory speed for laying the liquids upon the cake. The arrangementshown is subject to modification in accordance with the nature of theseparation to be effected and the liquids to be discharged from thepipes |26.

To assist the ejector |04 in the proper discharge of the solid fraction,the ends of the spokes |01 adjoining the cylindrical 'walls of thebasket |02 are connected by a conical flange |43 which directs thesolids, under the action of centrifugal force, against a discharge ring|44 which may be mounted in any convenient man.- ner and arranged forrotation at a speed which is relatively low with respect to that of thebasket |02. For this purpose I have provided the ring |44 with asupporting flange |45 to the under side of which is secured a ring gear|45 meshing with a series of pinions |41 carried on studs secured to thewall |39. One of the pinions |41 is keyed to a drive shaft |48 to whichis secured a worm gear |49 driven from a worm |50 secured to the shaftof the motor r| I3.

The discharge ring |44 may be supported and driven in any other mannerwhich may be desired. For example, it would be possible to support thering on friction Wheels or discs instead of on. the pinions |41. Thesolids discharged from the basket cling to the walls of the dischargering |44 under the action of centrifugal force until' they are removedtherefrom by the action of a scraper |5| secured to the bottom 96 of thecasing 9| adjacent the discharge outlet |52. The scraper |5| may besecured in place by means of a bracket |53 or it may be welded directlyto the bottom of the casing. In the event that the material dischargedfrom the basket is of such a character as to stick to the ring |44,auxiliary means may be provided for scraping the bottom 96 of thecasing, such as radial planes or spokes extending inwardly from thering.

It will be understood that the principle of operation of the verticalembodiment illustrated in Figs. 11, 12, and 13 is the same as has beendescribed with reference to the horizontal type. With the speeds aspreviously assumed, the cams |2| and |22 are pushed apart approximately50 times per minute. As in the case of the horizontal type, thedirection of rotation of the basket and ejector may be either clockwiseor counterclockwise (looking into the machine from the discharge end).If clockwise, the helical element of the ejector will be in the form ofa lefthand screw; if counterclockwise, a right-hand screw. Also, theejector may be geared to run faster, instead of slower, than the basket,always remembering that the pitch and direction of the screw should beso related to the magnitude and direction of the speed differential, anddesign of the cams, as to produce a screwing-in action which avoids anysubstantial displacement of the cake with respect to the basket exceptduring the intermittent bodily longitudinal movement of the ejector.Other modifications will suggest themselves to those skilled in the art.The terms and expressions which I have employed are used as terms ofdescription and not of limitation, and I have no intention of excludingsuch equivalents of the invention set forth, or of portions thereof, asfall within the purview of the claims.

I claim:

1. The method of separating the liquid and solid fractions of a materialwhich comprises feeding the material continuously into a substantiallycylindrical chamber having perforated side walls and an end open for thedischarge of material, rotating the chamber to drive out liquidfractions by centrifugal force, and periodically ejecting a portion ofthe solid fraction by screwing a helical element into the materialwithout substantial displacement of the material and intermittentlymoving said element longitudinally of the chamber to advance thematerial bodily toward the discharge end of the chamber.

2. The method of separating the liquid and solid fractions of a materialwhich comprises feeding the material continuously into a substantiallycylindrical chamber having perforated side Walls and an end open for thedischarge of material, rotating the chamber to drive out liquidfractions by centrifugal force, and periodically ejecting a portion ofthe solid fraction by screwing a helical element into the material at acontrolled rate of longitudinal movement such that for each revolutionof the element relative to the chamber said element moves a longitudinaldistance substantially equal to the pitch of the helix7 andintermittently moving said element longitudinally of the chamber toadvance the material toward the discharge end of the chamber.

3. The method of separating the liquid and solid fractions of a materialwhich comprises feeding the material continuously into a substantiallycylindrical chamber having perforated side Walls and an end open for thedischarge of material, rotating the chamber to drive out liquidfractions by centrifugalforce, and periodically ejecting a portion ofthe solid fraction by screwing a helical element into the material andintermittently moving said element bodily longitudinally of the chamberto advance the material toward the discharge end of the chamber, andcontrolling the rate of longitudinal travel of the element during boththe screwing and bodily movements.

4. The method of separating the liquid and solid fractions of a materialwhich comprises feeding the material continuously into a substantiallycylindrical chamber having perforated side Walls and an end open for thedischarge of material, rotating the chamber to drive out liquidfractions by centrifugal force, and periodically ejecting a portion ofthe solid fraction by screwing a helical element into the material andintermittently moving said element bodily longitudinally of the chamberto advance the material toward the discharge end of the chamber, andcontrolling the rate of longitudinal travel of the element during boththe screwing and bodily movements so that said rate will besubstantially greater during the bodily movement than during thescrewing movement.

5. The method of separating the liquid and solid fractions of a materialwhich comprises feeding the material continuously into a substantiallycylindrical chamber having perforated side walls and an end open for thedischarge of material, rotating the chamber to drive out liquidfractions by centrifugal force, and periodically electing a portion ofthe solid fraction by screwing a helical element into the material andintermittently moving said element bodily longitudinally of the chamberto advance the material tov/ard the discharge end of the chamber, andcontrolling the rate of longitudinal travel of the element during boththe screwing and bodily movements so that said rate will be synchronizedwith the pitch of the helix during the screwing movement.

6. The method of separating the liquid and solid fractions of a materialwhich comprises feeding the material continuously into a substantiallycylindrical chamber having perforated side Walls and an end open for thedischarge of material, rotating the chamber to drive out liquidfractions by centrifugal force, and periodically ejecting a portion ofthe solid fraction by screwing a helical element into the material andintermittently moving said element bodily longitudinally of the chamberto advance the material toward the discharge end of the chamber, andcontrolling the rate of longitudinal travel of the element during boththe screwing and bodily movements so that said rate will be synchronizedwith the pitch of the helix during the screwing movement and will bemuch more rapid during the bodily movement.

'7. Apparatus for separating the liquid and solid fractions of amaterial which comprises a substantially cylindrical chamber havingperforated side Walls and an end open for the discharge of material,means for feeding the material continuously into the chamber, asubstantially cylindrical helical element disposed within the chamberand extending longitudinally thereof, said element comprising a helicalportion extending at least for one turn about the longitudinal axisthereof, means for rotating the chamber to drive out liquid fractions bycentrifugal force, and means for screwing the helical element into thematerial in the chamber Without substantial displacement of the materialand for intermittently moving the helical element longitudinally vof thechamber to advance the material bodily toward the discharge end of thechamber.

8. Apparatus for separating the liquid and solid fractions of a materialwhich comprises a substantially cylindrical chamber having perforated`side Walls and an end open for the discharge of material, means forfeeding the material continuously into the chamber, a substantiallycylindrical helical element disposed within the chamber and extendinglongitudinally thereof, said element comprising a helical portionextending vat least for one turn about the longitudinal axis thereof,means for rotating the chamber to drive out liquid fractions bycentrifugal force, means for screwing the helical element into thelmaterial in the chamber, means forcontrolling the rate of longitudinalmovement of the helical element so that for each revolution of theelement it moves a longitudinal distance substantially equal to thepitch of the helix of said element, and means for intermittently movingsaid element bodily longitudinally of the chamber to advance thematerial toward the discharge end of the chamber.

9. Apparatus for separating the liquid and solid fractions of a materialwhich comprises a substantially cylindrical chamber having perforatedside walls and an end open for the discharge of material, means forfeeding the material continuously into the chamber, a substantiallycylindrical helical element disposed Within the chamber and extendinglongitudinally thereof, said element comprising a helical portionextending at least for one turn about the longitudinal axis thereof,means for rotating the chamber to drive out liquid fractions bycentrifugal force, means for screwing the helical element into thematerial in the chamber in one direction, and means for moving saidelement bodily in the opposite direction.

10. Apparatus for separating the liquid and solid fractions of amaterial which comprises a substantially cylindrical chamber havingperforated side walls and an end open for the discharge of material,means for feeding the material continuously into the chamber, asubstantially cylindrical helical element disposed within the chamberand extending longitudinally thereof, said element comprising a helicalportion eX- tending at least for one turn about the longitudinal axisthereof, means for rotating the chamber to drive out liquid fractions bycentrifugal force, means for rotating the helical element at a speedwhich is different than the speed of the chamber, means forreciprocating said element longitudinally of the chamber, and means forcontrolling the rate of reciprocation to avoid substantial displacementof the material When reciprocating in one direction and to producesubstantial displacement of the material when reciprocating in theopposite direction.

HENRI G. CHATAIN`

